Balanced system considerations
In situations where you are monitoring a balanced 3-phase
load, you may choose to connect only one or two CTs on the phase(s) you want to measure,
and then configure
the meter so it calculates the current on the unconnected current input(s).
NOTE: For a balanced 4-wire Wye system, the meter’s calculations
assume that there is no current flowing through the neutral conductor.
Balanced 3-phase Wye system with 2 CTs
The current for the unconnected current input is calculated so that the vector sum for all three phases equal zero.
Balanced 3-phase Wye or Delta system with 1CT
The currents for the unconnected current inputs are calculated so that their magnitude and phase angle are identical and equally distributed, and the vector sum for all three phase currents equal zero.
NOTE: You must always use 3 CTs for 3-phase 4-wire center-tapped
Delta or center-tapped open Delta systems.